A high-density (HD) imaging array with 158 sources and 166 detectors (Fig. REF  first column) [1]} was placed over the whole head, with source-detector (SD) separation distances ranging from 1.3 to 4.8cm. In this study, 3478 differential measurements per wavelength were used to image hemodynamic changes in the brain. Two distinct anomalies were simulated simultaneously in the brain, with each 15mm radius. In order to simulate the traumatic brain injury (TBI) cases where tissue oxygen saturation (\(\rm {StO_2}\) ) is normally between 50% and 75% [2]}, [3]}, the absorption coefficient in the two anomalies are calculated using Beer's law [4]} with 55% \(\rm {StO_2}\)  (Fig. REF  second column). In line with the expected in vivo performance of the imaging system, 0.12\(\%\) , 0.15\(\%\) , 0.41\(\%\)  and 1.42\(\%\)  Gaussian random noise was added to first (13mm), second (30mm), third (40mm) and fourth (48mm) nearest neighbor measurements to provide realistic data [5]}. Reconstructed absorption coefficients using different model are displayed in the third to fifth column of Fig. REF . Corresponding 2D slices are displayed in Fig. REF  and the evaluation metrics are presented in Fig. REF .
